|Filter beds showing Spanish Broom along the riverside wall|
Any discussion about the vegetation on the Filter Beds must start with the Spanish Broom, which when in full yellow glory, forms a landmark in the area. For us it is characteristic of and special to Surbiton, something local residents can feel pride, when a visitor remarks on their surprise glimpse of gold, whilst visiting the district. For small songbirds it provides the main structure for nesting, a refuge from predators; as well as loafing and foraging habitat. What does it matter that it is non-native, when providing such useful functions and giving pleasure to those who view it? Generally there is no problem with most non-native species in urban areas providing they are not invasive. Our Local Nature Reserves are full of non-native species from sycamore and chestnut trees to the usual garden escapes such as asters, golden rod and Himalayan Balsam. They are favoured by pollen and nectaring insects and are better for wildlife than tarmac, gravel and concrete. Across London they can be localised indicators of past landuse especially the industrial heritage along Bow Back river wharfes. Plants such as Mexican tea (which smells like creosote) Sumatran fleabane Conyza sumatrensis and Bermuda Grass are endemic to the area.......we have our Spanish broom.
The London Ecology Unit Handbook 1992 entry on Seething Wells states 'Several wildlflowers normally associated with the dry clacareous grasslands further south have gained a northern outpost on this unusual site'. The secret of the species rich grassland is that for 160 years from the construction of the reservoirs to the present day, no pesticides or fertilisers have been used for fear of contaminating the drinking water. This has promoted a nutrient poor fine sward which favours wild flowers.
Some of the plants found around the Filter beds are characterised as rare in London and included three scabious species including small scabious, reflexed stonecrop,dropwort, restharrow, fern grass and common broomrape.